6.9 in a bus needs radiator. Upgrades?

Ferdy Mint

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Sounds like you have a big budget. Let me be the stool in the punch bowl and suggest that a 430/6.9 is not for you. I'd just let one of our vendors here build you a healthy sleeved 445/7.3 TIDI with a big IP and aftercooler, add bigger radiators and by that I mean all of them, and rock n roll that way. You'd finally make it to 70 mph.

If money's an issue, bolt it together yourself. I love wrenching on clean new parts.
 

Luke_IDI

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As much as I could get.

Plan was to max a stock IP. I was on the fence about switching to arp studs. If I kept the bolts, I'd just max the stocker and let it go until/if it blew the gaskets. If I upgraded pumps, I feel you'd have to install studs. If I'm going to install studs, I might as well build the spare 7.3 and have more displacement and thicker studs.

TP38 should have worked fine. I wasn't wanting 400 hp and 50 psi, just something better then NA that wouldn't cut down on reliability. I actually had that .84 housing bookmarked, along with a kc s300 turbine wheel and a wicked wheel 2. I was on the fence between the .84 housing and the 1.0 housing. I figured I wasn't burning enough fuel with a stock pump to worry about the .84 being too small.

I think I remember years ago reading that calvin(towcat) had a favorable review on a tp38 swapped IDI, but I can't find that post any more.
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Referenced from R&D's "The IDI Turbocharger Thread" on FTE.

Looks like this thing would really start running out of boost capacity around 25-30 psi. 10-15 psi looks like it would put you right in the middle efficiency island.

It seems easy enough to calculate where you'll likely fall on the map at max fueling that your pump is capable of, but I'm still having trouble figuring out how to predict what turbo efficiency/boost is going to look like at partial throttle. I know there's some trial and error involved. Still, it looks like it couldn't be too bad on this turbo, especially with a smaller exhaust housing (diagram is for the 1.10 A/R).

Is there any reason not to drop head studs in by removing the head bolts one at a time and replacing with studs, without removing the heads? All are very easily accessible on the bus (I understand that the heads, or the motor, must be removed to do studs in a truck), and I've already had the heads off in the past year, so that might be part of my plan from the get go, if the turbo looks like it's going to be making more than 12 psi or so of boost.

I live three hours away from where the bus is currently parked, so I have trouble envisioning certain parts about the engine bay layout sometimes. I looked back at some photos I have, though, and found that the exhaust manifolds are nestled pretty well up against the frame rails. I had the idea to buy another of the stock 90 degree exhaust manifolds and flip both so the outlets point up-ish, then run up-pipes along to the back of the engine bay, toward the center to meet each other, and to a turbo in more or less the conventional location. But looking at these pictures, I am not even sure if there would be room to flip one of the manifolds due to frame rail clearance. Did it look like the Rayjay manifold was going to clear the frame rails ok?

Issues with firewall clearance, issues with frame rail clearance....such a big engine bay, so little room in the critical places for turbo pipe routing! When I get have the time and money to really work on the mods (which will probably be in the spring) I will see if I can flip one manifold or the other over--somehow this seems promising to me. But in another development of modification temptation....I found listed locally a running DT466 (180k mi, appears to have an MW pump) mated to an MT643. $3,000 for the pair. If I were a little closer to getting started on the mods timewise, location-wise, and finances-wise, I'd consider trying to make a deal and scrapping my IDI plans!
 

IDIBRONCO

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Is there any reason not to drop head studs in by removing the head bolts one at a time and replacing with studs, without removing the heads?
Personally, I would never do this. You have no way to clean the crud out of the threads. Even though they only have a few thousand miles on them, you'd still be using 35+ year old head gaskets. Why would you not want to run new head gaskets?
 

Luke_IDI

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Sounds like you have a big budget. Let me be the stool in the punch bowl and suggest that a 430/6.9 is not for you. I'd just let one of our vendors here build you a healthy sleeved 445/7.3 TIDI with a big IP and aftercooler, add bigger radiators and by that I mean all of them, and rock n roll that way. You'd finally make it to 70 mph.

If money's an issue, bolt it together yourself. I love wrenching on clean new parts.
I'm not sure what about this thread leads you to believe I have a big budget. If I did have several extra thousand lying around for maximizing the capabilities of this vehicle, I'd probably have swapped in a DT466 long before I even became familiar enough with the IDI to ask the questions in this thread. Have a vendor build me a fresh engine? To the tune of what, $5,000+? This thread is about how to make a specific chassis, the International S1700, work for a specific use profile, with used parts available on a budget. We're talking about using stock IP's here, which from my inexperienced understanding is probably not even going to blow any head gaskets, let alone get you into the realm of challenging ARP studs on a 6.9.

Edit: R&D's base price for an "enhanced long block" not including injectors, IP, turbo, or turbo kit: $6,500.
 
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Luke_IDI

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Personally, I would never do this. You have no way to clean the crud out of the threads. Even though they only have a few thousand miles on them, you'd still be using 35+ year old head gaskets. Why would you not want to run new head gaskets?
In the very next sentence following the one you quoted, I said that I have had the heads off less than a year ago. So you must also be wondering how I managed to reuse my 35 year old head gaskets....LOL I'll start a separate thread on this, to which the budget-conscious among us will definitely want to subscribe....;)

The head gaskets I installed were marked "Felpro" and looked pretty dang NEW. So the head gaskets on the engine have about one year and 1,000 miles on them, which is why I would prefer not to pull the heads, unless there is a good reason not to remove and replace one bolt at a time. Also, I've found a homemade bottoming tap/thread chaser works very nicely for drawing crud up and out of threads. I don't see why one couldn't just chase/clean the threads with a long bottoming tap.
 

IDIBRONCO

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In the very next sentence following the one you quoted, I said that I have had the heads off less than a year ago. So you must also be wondering how I managed to reuse my 35 year old head gaskets....LOL I'll start a separate thread on this, to which the budget-conscious among us will definitely want to subscribe....;)

The head gaskets I installed were marked "Felpro" and looked pretty dang NEW. So the head gaskets on the engine have about one year and 1,000 miles on them, which is why I would prefer not to pull the heads, unless there is a good reason not to remove and replace one bolt at a time. Also, I've found a homemade bottoming tap/thread chaser works very nicely for drawing crud up and out of threads. I don't see why one couldn't just chase/clean the threads with a long bottoming tap.
So then, why even bother to ask? Just do it.
 

Booyah45828

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Else, best limit your boost to whatever Banks does. Banks is always conservative. You won't be cruising a bus at 65-70 mph with only 4 psi of boost, frankly.
On flat ground I can get mine to 70 after a couple miles, foot to the floor, on the governor @ 3500 rpm. All naturally aspirated. I honestly could probably do better if the gearing were better, but I'm not going to, at least not without a turbo, intercooler, and better transmission.

On a 6.9, studs would be HIGHLY suggested. But brian(IDIoit) has his twin turbo build on 7.3 head bolts, and hasn't blown the gaskets yet.

I think with a decent turbo, intercooler, and the boost level conservative, you won't pop the 6.9 gaskets.
 
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Luke_IDI

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So then, why even bother to ask? Just do it.
Well, I was more concerned about whether there is an issue with relieving and then reapplying pressure in an uneven fashion, more from the point of view of stress factors on the heads. This could be a ridiculous concern but I don't know anything about it, so I thought I'd ask.
 

Luke_IDI

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On flat ground I can get mine to 70 after a couple miles, foot to the floor, on the governor @ 3500 rpm. All naturally aspirated. I honestly could probably do better if the gearing were better, but I'm not going to, at least not without a turbo, intercooler, and better transmission.

On a 6.9, bolts would be HIGHLY suggested. But brian(IDIoit) has his twin turbo build on 7.3 head bolts, and hasn't blown the gaskets yet.

I think with a decent turbo, intercooler, and the boost level conservative, you won't pop the 6.9 gaskets.
I'm sure I would be more than willing to challenge the limits of stock head bolts were we talking about a pickup (not that IDIoit's is!), where I could use my normal roadside assistance. But as it's in a bus, reliability is key. Not that vehicles are always completely undriveable with blown head gaskets, but as soon as you get water emulsified into your oil, the engine is a ticking (knocking?) time bomb, and I'd be hesitant to drive it even a little if that happened. I'd probably put studs in with the rationale that they would cost far less than a single tow.
 

Booyah45828

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Referenced from R&D's "The IDI Turbocharger Thread" on FTE.

Looks like this thing would really start running out of boost capacity around 25-30 psi. 10-15 psi looks like it would put you right in the middle efficiency island.

It seems easy enough to calculate where you'll likely fall on the map at max fueling that your pump is capable of, but I'm still having trouble figuring out how to predict what turbo efficiency/boost is going to look like at partial throttle. I know there's some trial and error involved. Still, it looks like it couldn't be too bad on this turbo, especially with a smaller exhaust housing (diagram is for the 1.10 A/R).

Is there any reason not to drop head studs in by removing the head bolts one at a time and replacing with studs, without removing the heads? All are very easily accessible on the bus (I understand that the heads, or the motor, must be removed to do studs in a truck), and I've already had the heads off in the past year, so that might be part of my plan from the get go, if the turbo looks like it's going to be making more than 12 psi or so of boost.

I live three hours away from where the bus is currently parked, so I have trouble envisioning certain parts about the engine bay layout sometimes. I looked back at some photos I have, though, and found that the exhaust manifolds are nestled pretty well up against the frame rails. I had the idea to buy another of the stock 90 degree exhaust manifolds and flip both so the outlets point up-ish, then run up-pipes along to the back of the engine bay, toward the center to meet each other, and to a turbo in more or less the conventional location. But looking at these pictures, I am not even sure if there would be room to flip one of the manifolds due to frame rail clearance. Did it look like the Rayjay manifold was going to clear the frame rails ok?

Issues with firewall clearance, issues with frame rail clearance....such a big engine bay, so little room in the critical places for turbo pipe routing! When I get have the time and money to really work on the mods (which will probably be in the spring) I will see if I can flip one manifold or the other over--somehow this seems promising to me. But in another development of modification temptation....I found listed locally a running DT466 (180k mi, appears to have an MW pump) mated to an MT643. $3,000 for the pair. If I were a little closer to getting started on the mods timewise, location-wise, and finances-wise, I'd consider trying to make a deal and scrapping my IDI plans!
I thought the tp38 would be good too. People rave in the trucks when going NA to Turbo, even if they get 5-10 psi out of it. I figured 15 and a maxed pump and I would be more then pleased. Truthfully, I was going to max the pump to whatever the pyro said I could run, and let the boost # lie where it falls.

It'd be close between frame and manifold. I think it'd fit, as my frame is already notched from the factory for room. Push comes to shove I'd notch it more.

I considered swapping bolts to studs, and I see no issue with it gasket wise, but I'd be sure the heads and valve guides are in great shape, or I'd remove the heads and have them done. My biggest worry was snapping off one of the exterior bolts due to rust, but going slow with an impact and plenty of kroil was the plan. If one broke, off came the heads anyways.

Your's being recently replaced, I see no problem swapping bolt for stud. And in a bus it'd totally doable, unlike a truck or van.

You can get long shank taps, tap extenders, and the like to get it done. I was going to use a piece of ready rod cut to length, grind some flutes into it to hold the debris, and then heat it up and quench it for a little hardness. You can get ready rod for a few bucks, and it doesn't have to be tool steel, as it's not actually cutting any threads.

IDK, I thought of swapping a DT in as well. but then you have the dog house to find/build, and depending on the year and hp of the DT, you'd still be regearing and everything. One of the cool features of the DT series engines is it's ability to be inframed, one of the uncool features is that those liners use o-rings to seal, and if it's never had the o-rings replaced, I'd plan on doing it.
 

Booyah45828

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I'd probably put studs in with the rationale that they would cost far less than a single tow.

That's correct. Studs would probably be your best bet then.

My thought was if I'm going to stud it, I might as well stud the spare 7.3 and run that then. Then I'd be good with any boost a stock pump could make. RnD also ran a test on headbolts and breakage, and surprisingly the 6.9 bolts did fairly well, at least compared to the 7.3 units and how they've always been considered "trash". It was on a forum somewhere, but he jumped to so many different ones I can't begin to tell you where to look for it.

With alloy heads/blocks you have to worry about stuff moving around when removing bolts, but I don't think you'll have an issue with an idi. Heck, some alloy heads you've got to remove the bolts an 1/8 turn and in a sequence or you'll warp the head.
 

Booyah45828

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I've got a feeling this thread is bad for me, I'm getting 2nd thoughts on selling and finishing it out instead lol
 

Luke_IDI

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I thought the tp38 would be good too. People rave in the trucks when going NA to Turbo, even if they get 5-10 psi out of it. I figured 15 and a maxed pump and I would be more then pleased. Truthfully, I was going to max the pump to whatever the pyro said I could run, and let the boost # lie where it falls.
That's about the approach I would take as well. I was also guessing 15 psi, and would be very happy to see that. Also, seems like it would make sense to get everything rigged up and running with the driveline mods and then see if a smaller turbine housing for lower-range boost would be desirable. Seems like both 1.0 and .84 housings are available, both smaller than stock.
It'd be close between frame and manifold. I think it'd fit, as my frame is already notched from the factory for room. Push comes to shove I'd notch it more.
Notched frame from the factory? About how much is it notched? Care to share a pic? Mine is not notched. Doing that on my own project would make me a little nervous, as understanding frame strength and stresses at this scale is not something I know anything about. I'd be curious to know how much notching IH thought was allowable--wouldn't have a problem with that, I suppose.
I considered swapping bolts to studs, and I see no issue with it gasket wise, but I'd be sure the heads and valve guides are in great shape, or I'd remove the heads and have them done. My biggest worry was snapping off one of the exterior bolts due to rust, but going slow with an impact and plenty of kroil was the plan. If one broke, off came the heads anyways.

Your's being recently replaced, I see no problem swapping bolt for stud. And in a bus it'd totally doable, unlike a truck or van.
I forgot to mention before that when the heads were off in the first place, a cracked head was discovered. The machine shop had a fresh reman on hand to replace it, so we bought that and had them redo the other to match. So yeah, really no reason for them to come off if they don't have to. I'm just looking at the difference in torque specs for ARP studs on the 6.9 according to IDI Online. 6.9 studs to 80 ft-lbs, 7.3 studs to 125 ft-lbs. I knew there was a difference between them, but I didn't realize it was that significant. So that's why people sleeve 7.3 blocks to 6.9. I'll keep in mind building my spare 7.3 as well for when the turbo project happens, and swapping all of the commercial bits from the 6.9 over. I think the 7.3 I have is a turbo block as well. I haven't confirmed that yet though, and I have the engine in storage across the country at the moment.

IDK, I thought of swapping a DT in as well. but then you have the dog house to find/build, and depending on the year and hp of the DT, you'd still be regearing and everything. One of the cool features of the DT series engines is it's ability to be inframed, one of the uncool features is that those liners use o-rings to seal, and if it's never had the o-rings replaced, I'd plan on doing it.
Yes, I forgot those buses have doghouses. Even though the DT466 is only 3" longer nose to tail than an the IDI, it's taller, and that's where all the firewall interference would be. I wonder if one would run into clearance issues at the radiator.

But this reminds me that the firewall in the bus is closest to the IDI right at the top edge of the valve covers, then slopes down and back toward the floor. From my pictures, it looks like there might be room to run an up pipe from the passenger side manifold under there (sort of over the flywheel housing/bellhousing area). Assuming the passenger side mounted turbo, it would probably be a run of similar length to going over the valve cover, and out of the way of injector lines/IP/glow plugs. Too bad the stock exhaust manifold that's closer to straight would point up, not down, if installed on the passenger side. Could fabricate a manifold to do this. In the name of scavenging all possible, though, I do think it would be neat to come up with a way to use the stock manifolds somehow or other. Not at all committed to that principle, though. And about that up pipe routing, I'm not sure about all that heat right under my feet on a warm day.

We might drive over to where the bus is this weekend and tinker a bit. I'll go armed with a piece of exhaust pipe for a measuring tool and see what I can sketch out.
 

Booyah45828

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Fired the bus up today. I'm hoping to camp in it next weekend, and we're setting up camp tomorrow. This waiting til the last minute stuff might be comical if I didn't seemingly run everything in my life like that LOL:oops:.

Batteries were dead, no real surprise after sitting since November. Hooked the truck up to it with jumper cables, fired up the generator with a battery charger, and let it charge for an hour. Hopped back in, lit the glow plugs for 10 seconds, pumped the throttle and the ol girl cranked for not even a second and purred like a kitten. I really should take a video of it, as it's almost comical how good mine starts compared to half the starting videos I've watched.

Anyways, I took the pictures finally of what I said I would. You can see the frame cut in the first and 2nd, and then see the bae turbo manifold that I have in the 3rd. It will be close, but I'm pretty sure I would have clearance for the manifold-frame.
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This pic show the frame, where the flange goes from an inch or so wide near the manifold, to much wider back behind the engine.
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This is a side shot of the manifold installed on the spare engine. I think it'd be close, a tape measure says I'll have 3/4 of an inch clearance, and my eyeball says we're good.
 
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